Domestic clothes dryer and method for driving such dryers

ABSTRACT

A domestic clothes dryer includes a rotating drum that defines a drying chamber, an air inlet upstream the drum, and a lifter coupled to the drum. The lifter is in communication with the air inlet for distributing air inside the drum through a plurality of openings. The air inlet includes a shaped air plenum chamber facing a lower portion of a rear perforated wall of the drum and capable of delivering air to said lifter and/or directly to the drum through the rear perforated wall.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application represents a continuation application of andclaims priority of U.S. patent application Ser. No. 16/674,592, entitled“Domestic Clothes Dryer and Method for Driving Such Dryers”, filed Nov.5, 2019, currently pending, and also represents a continuationapplication of and claims priority to U.S. Pat. No. 10,501,885, entitled“Domestic Clothes Dryer and Method for Driving Such Dryers”, filed May4, 2017, and also claims priority to U.S. patent application Ser. No.14/173,166, entitled “Domestic Clothes Dryer and Method for Driving SuchDryers”, filed Feb. 5, 2014, now abandoned, and further claims priorityfrom European Patent Application 13154316.7 filed on Feb. 7, 2013, allof which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to clothes dryers and, more particularly,to clothes dryers that distribute air through one or more lifters.

BACKGROUND

JP-A-9056991 describes a lifter fixed at the periphery part of a rotarydrum and cylindrical seals are fixed at the outer periphery of an airintake plenum and of an air exhaust plenum, so that a circulationpassage is formed on the back of the rear wall of the drum. The use oftwo concentric air plenum chambers are related seals makes the aboveknown solution quite complex and not easy to be implemented. Moreover inthe above known solution the process hot air is flowing always andentirely through the lifters, even if the lifters are in an upperposition during drum rotation. In this condition, i.e. when the liftersare not in contact with clothes, the effectiveness of having air flowingin the lifter is substantially reduced. Another disadvantage of theabove known solution is that it cannot be adapted to traditional dryerswhere air flow enters the drum from a perforated rear wall and leavesthe drum from an aperture placed adjacent the front opening of the drum.

SUMMARY

It is an object of this disclosure to provide a tumble clothes dryerthat does not present the above disadvantages and which can providehigher drying performances, better fabric care and reduced wrinkles.

The above object is reached thanks to the features listed in theappended claims.

According to a first aspect of the present disclosure, a clothes dryerincludes a rotating drum, a lifter, and a shaped air plenum chamber. Therotating drum includes a rear perforated wall and a side wall. The rearperforated wall and the side wall at least partially define a dryingchamber. The lifter extends over at least a portion of a first surfaceof the rear perforated wall. The lifter extends over at least a portionof the side wall. The lifter includes a base portion that is coupled tothe rear perforated wall to define an inner chamber therebetween. Thelifter includes a plurality of openings to convey air from inside thelifter into the rotating drum. The shaped air plenum chamber deliversair through the rear perforated wall into the base portion of the lifterwhen the lifter is in a first pre-determined position relative to theshaped air plenum chamber. The shaped air plenum chamber delivers airthrough the rear perforated wall directly into the rotating drum in aregion that is circumferentially adjacent to the base portion of thelifter when the lifter is in the first pre-determined position relativeto the shaped air plenum chamber.

According to a second aspect of the present disclosure, a clothes dryerincludes a rotating drum, a lifter, and a shaped air plenum. Therotating drum includes a rear perforated wall and a side wall. The sidewall extends from the rear perforated wall. The side wall defines acircumference of the rotating drum. The rear perforated wall and theside wall at least partially define a drying chamber. The lifter extendsover at least a portion of a first surface of the rear perforated wall.The lifter extends over at least a portion of the side wall. The lifterincludes a base portion coupled to the rear perforated wall to define aninner chamber therebetween. The lifter includes a plurality of openingsto convey air from inside the lifter into the rotating drum. The baseportion of the lifter defines a first surface area through which air isreceived from the rear perforated wall. The shaped air plenum chamberfaces a second surface of the rear perforated wall. The shaped airplenum chamber includes a second surface area through which air isdelivered to the rear perforated wall. The second surface area isgreater than the first surface area. The shaped air plenum chamberdelivers air through the rear perforated wall into the base portion ofthe lifter when the lifter is in a first pre-determined positionrelative to the shaped air plenum chamber. The shaped air plenum chamberdelivers air through the rear perforated wall directly into the rotatingdrum in a region that is circumferentially adjacent to the base portionof the lifter when the lifter is in the first pre-determined positionrelative to the shaped air plenum chamber.

These and other features, advantages, and objects of the presentdisclosure will be further understood and appreciated by those skilledin the art by reference to the following specification, claims, andappended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and features of this disclosure will be clear fromthe following detailed description, with reference to the attacheddrawings, in which:

FIG. 1 is an isometric view of an example clothes tumble dryer;

FIG. 2 is an isometric enlarged view of the inside of the drum of FIG.1;

FIG. 3 is an isometric view of the rear of the drum of FIGS. 1 and 2;

FIG. 4 is a partial cross-sectional view of a detail of FIG. 2;

FIG. 5 is a front view of the perforated rear wall of the drum where theshape of the distributor is shown in solid and dotted line; and

FIG. 6 is a schematic view of how a clothes dryer according to thisdisclosure works.

DETAILED DESCRIPTION

With reference to FIG. 1, an example tumble dryer 10 includes a cabinet12 having an upper wall 12 a, a front wall 12 b provided with a hingedlymounted door 14, side walls 12 c and a rear wall 12 d. Inside thecabinet 12 a rotating drum 16 is mounted which is actuated by anelectric motor (not shown) and which defines a drying chamber 17. Thedrum 16 includes at least one lifter 18 having a plurality of holes 20for air passage. The lifter 18 may be hollow. The lifter 18 includes arear base portion 18 a covers a portion of a rear perforated wall 16 aof the drum in order to convey air entering through the perforated wall17 a towards the holes 20 of the lifter 18. The rear base portion 18 amay have a triangular or circular sector shape. The base portion 18 adefines with the facing portion of the rear wall 16 a of the drum 16 asort of inner chamber 19 (see FIG. 4) which covers an arc rangingpreferably from 60° to 100° and which communicates with the portion ofthe lifter 18 fixed to the side wall of the drum 16. The clothes dryer10 may also have a dispensing system for dispensing treating chemistriesinto the drum 16, and including a reservoir 22 that is closed by a cover24. The clothes dryer 10 is also provided with a controller 26 that mayreceive input from a user through a user interface 28 for selecting acycle of operation.

The clothes dryer 10 also includes an air inlet channel 30 (see FIG. 6)and an outlet channel 32, a heating system (not shown) that heats airentering the drum (e.g. by means of resistors, heat exchangers, etc.),and a blower (not shown) that makes air flowing across the drum 16.

The drum outlet 32, where a removable filter 33 for removing fluff orlint is placed, can be eventually connected to the drum inlet 30 thusrealizing a closed loop system in which heat exchangers, resistors, heatpump, etc. control the condensation and heating process. As analternative the drum outlet 32 can be connected to an air vent.

The lifter 18 functions not only to increase the heat exchangeefficiency between air and clothes and improve the evenness of thedrying result by means of clothes redistribution during the whole cycle,but also to improved the efficiency of hot air distribution.

A common drawback of known dryers is that when the load size increasesto almost fill the drum volume, the efficiency of the lifter inredistributing the load within the drum is decreased thus leading to therisk of damaging the clothes that are positioned in the rear end of thedryer (where temperatures are higher) and reducing the evenness ofdrying results.

With a lifter design that allows not only the hot air to flow throughthe lifter 18 but also by means of a distribution of air through thelifter 18 only during a certain degree of rotation of the drum 16, thetemperature gradient in the drum 16 is reduced and the evenness ofdrying is increased, reducing also the risk of clothes damaging.

The above controlled distribution is carried out by means of a shapedfixed distributor 34 which forms an air inlet plenum chamber upstream ofthe drum 16. The shape of the distributor 34 (FIG. 5) does notnecessarily correspond to the circular sector shape of the base portion18 a of the lifter 18, but need not extend higher than the lower half ofthe drum 16. In FIG. 5, two shapes are shown (in dotted and solid lines)which have worked well in tests carried out by the applicants. Suchshapes maximize the air flow either through the lifter 18 (when thislatter is in the lower positions during rotation) and through clothesadjacent the lifter.

In other examples, the enhanced lifter design can be combined with adedicated cycle design, able to stop tumbling when the lifter 18 islocated in a position that minimizes the temperature gradient. Thisapproach can furthermore increase the above mentioned advantages and canprovide also energy saving benefits due to reduced motor usage. One ormore lifters of the type disclosed above can also be used together withone or more typical lifters that do not match the above description. Dueto the fact that the lifter 18 is physically connected to the drum 16,during tumbling it changes its position with respect to the air inlet 34thus leading to a variable air mass flow rate in the lifter 18 and inthe drum 16. This is clearly shown in FIG. 6 where arrows A show the airflow through the lifter 18 (when this latter is placed in the lowerposition inside the drum 16), and arrows B show the air flow through therear wall 16 a of the drum 16 when the lifter 18 is in a position notmatching the air distributor 34. This alternating air flow path in thedrum 16 creates the conditions for a variable heat flux as well thatimproves the evenness of drying the fabric care.

The examples disclosed herein can improve significantly also the dryingand fabric care performances with delicate cycles. As described above,aiming to reduce the mechanical action on this type of loads, thetumbling is often reduced or even avoided; this solution has thenegative result of increasing the temperature gradient thus leading tothe already discussed drawbacks. If the proposed lifter design is used,the machine can be designed to stop tumbling (for the whole cycle oronly for part of it, also e.g., using a PWM approach) in a way that theair can flow through the lifter 18 to provide a means to optimize heatflux for these type of loads using appropriate design of the lifter. Insome examples, the drum 16 is in a position where the lifter 18 lays onthe bottom of the drum 16, thus having the clothes laying on it. Themethod used to stop the drum 16 in the correct position is well known inthe art and it can be easily transferred from the known solutions fortop loader washer for having the door in upwards location to facilitateloading and unloading of the drum.

Moreover, since air can flow through the lifter 18, the latter can bedesigned to host a cartridge containing a fragrance or some otherchemical additives to improve quality of drying that can be released inthe drum 16.

In some examples, the lifter 18 is used with a drum 16 having an airinlet and outlet port on opposite sides thus enabling fine optimizationof heat fluxes. Nevertheless the examples disclosed herein can beapplied to those drums in which inlet and outlet air connections arelocated on the same side (with a dedicated air collector similar to airdistributor 34). In these examples the lifter 18 can be used to conveyhot inlet air towards the opposite side of the drum 16, thereforeimproving significantly the heat flux distribution in the longitudinaldirection.

FIG. 4 shows a detail of the air distributor 34 which is made preferablyby a shaped metal or plastic sheet 35. In order to increase theefficiency, a sealing means (not shown) can be interposed between theedge of the shaped sheet 35 forming the distributor 34 and the rear wall16 a of the drum 16.

1. A clothes dryer comprising: a rotating drum having a rear perforatedwall and a side wall, wherein the rear perforated wall and the side wallat least partially define a drying chamber; a lifter extending over atleast a portion of a first surface of the rear perforated wall, thelifter extending over at least a portion of the side wall, the lifterhaving a base portion coupled to the rear perforated wall to define aninner chamber therebetween, the lifter having a plurality of openings toconvey air from inside the lifter into the rotating drum; and a shapedair plenum chamber that delivers air through the rear perforated wallinto the base portion of the lifter when the lifter is in a firstpre-determined position relative to the shaped air plenum chamber,wherein the shaped air plenum chamber delivers air through the rearperforated wall directly into the rotating drum in a region that iscircumferentially adjacent to the base portion of the lifter when thelifter is in the first pre-determined position relative to the shapedair plenum chamber.
 2. The clothes dryer of claim 1, wherein the baseportion of the lifter defines a first surface area through which air isreceived from the rear perforated wall.
 3. The clothes dryer of claim 2,wherein the shaped air plenum chamber comprises a second surface areathrough which air is delivered to the rear perforated wall, and whereinthe second surface area is greater than the first surface area.
 4. Theclothes dryer of claim 1, wherein the shaped air plenum chamber deliversair through the rear perforated wall directly into the rotating drumwhen the lifter is in a second pre-determined position relative to theshaped air plenum chamber.
 5. The clothes dryer of claim 1, wherein theshaped air plenum faces a second surface of the rear perforated wall ofthe rotating drum.
 6. The clothes dryer of claim 5, wherein the firstsurface of the rear perforated wall and the second surface of the rearperforated wall are on opposing sides of the rear perforated wall. 7.The clothes dryer of claim 1, wherein the shaped air plenum chamberfaces a lower portion of the rear perforated wall.
 8. The clothes dryerof claim 7, wherein an upper edge of the shaped air plenum chamber ispositioned below a center of the drying chamber.
 9. The clothes dryer ofclaim 1, wherein the side wall extends from the rear perforated wall.10. The clothes dryer of claim 9, wherein the side wall defines acircumference of the rotating drum.
 11. The clothes dryer of claim 1,wherein the drying chamber is further defined by a door that is movablebetween an open position and a closed position.
 12. The clothes dryer ofclaim 1, further comprising: an air inlet upstream of the rotating drum,wherein air is delivered from the air inlet to the shaped air plenumchamber.
 13. The clothes dryer of claim 1, wherein the base portion hasa triangular sector shape.
 14. A clothes dryer comprising: a rotatingdrum having a rear perforated wall and a side wall, wherein the sidewall extends from the rear perforated wall, wherein the side walldefines a circumference of the rotating drum, and wherein the rearperforated wall and the side wall at least partially define a dryingchamber; a lifter extending over at least a portion of a first surfaceof the rear perforated wall, the lifter extending over at least aportion of the side wall, the lifter having a base portion coupled tothe rear perforated wall to define an inner chamber therebetween, thelifter having a plurality of openings to convey air from inside thelifter into the rotating drum, wherein the base portion of the lifterdefines a first surface area through which air is received from the rearperforated wall; and a shaped air plenum chamber that faces a secondsurface of the rear perforated wall, wherein the shaped air plenumchamber comprises a second surface area through which air is deliveredto the rear perforated wall, wherein the second surface area is greaterthan the first surface area, wherein the shaped air plenum chamberdelivers air through the rear perforated wall into the base portion ofthe lifter when the lifter is in a first pre-determined positionrelative to the shaped air plenum chamber, and wherein the shaped airplenum chamber delivers air through the rear perforated wall directlyinto the rotating drum in a region that is circumferentially adjacent tothe base portion of the lifter when the lifter is in the firstpre-determined position relative to the shaped air plenum chamber. 15.The clothes dryer of claim 14, wherein the shaped air plenum chamberdelivers air through the rear perforated wall directly into the rotatingdrum when the lifter is in a second pre-determined position relative tothe shaped air plenum chamber.
 16. The clothes dryer of claim 14,wherein the first surface of the rear perforated wall and the secondsurface of the rear perforated wall are on opposing sides of the rearperforated wall.
 17. The clothes dryer of claim 14, wherein the baseportion has a triangular sector shape.
 18. The clothes dryer of claim14, wherein the shaped air plenum chamber faces a lower portion of therear perforated wall.
 19. The clothes dryer of claim 18, wherein anupper edge of the shaped air plenum chamber is positioned below a centerof the drying chamber.
 20. The clothes dryer of claim 14, furthercomprising: an air inlet upstream of the rotating drum, wherein air isdelivered from the air inlet to the shaped air plenum chamber.